PWM not smooth on D3 pin on Nano

Other Hardware General Electronics
1

Hello!

I'm using a Nano to animate 6 LED strips with this code https://pastebin.com/nvE6QerP
So just fading up and down.

I'm using IRLB8743 MOSFETS for each strip and I have a problem that the LED strip which is on pin D3 is not completely turning off, but is having some flickerng at close to zero brightness.
The other LED strips behave normaly at zero and are pitch black.

I have eliminitaed the LED strip as the problem, because it works normally when I plug it to a different PWM pin.
I also replaced the MOSFET and the arduino.
The picture of the electroinics:

PXL_20221117_210505060
PXL_20221117_2105050601920×1442 263 KB

I't out of ideas, does anyone kow why this is happening?

Than you, Janezk

2

Help us help you.

Are you expecting the breadboard to provide amps of current?

3

Even for me it could be the fault of the breadbord.

4

The breadboard is supplying 1A @24V.
The problem is at 0, not at 222 brightness.
I don't understand why the breadboard would be a bottleneck at 0?

And the problem is only on one pin, not all of them.
Of course I can try bypassing the breadboard on the one problematic pin (but leave the res on the breadboard, because why fix it if it isn't broken and lose time which I don't have a lot of right now)

5

Swap D3 with another pin and find out which strip then does not go off.

6

You can spend weeks spinning your wheels or you may get lucky and get your problem solved. We cannot see what you have in detail so we ask for an annotated schematic as you have it wired showing all connections including power, ground, supplies etc. I will normally spend a moment on a question if it is missing information I need I ask, if somebody has asked for it, great but if it is missing that I wonder if the OP is serious and probably will just go to another question. We also know there are many modules etc that look alike and may be called the same thing but they are different, that is why we ask for links to "Technical Information". We also know a lot stuff is purchased from the azon marketplace by sellers that do not know what they are selling and they do not bother to add all the technical information.

7

First the solution in case anyone stumbles on this problem. Though I'm not sure why the solution works but in my case it did.

I removed the resistors used on the D3 pin - both the 10k pullup and the 220ohm on the gate.
And it worked, the LED strip didn't flicker at 0 anymore.
So I guess that before it didn't completely pull down even though I had a pulldown resistor, but after I removed it it worked.

Before that I eliminated faulty components because I replaced each component involved. Including the resistors and breadboard.

Thank you all for the help, I appreciate your time.

8

Mosfets can oscillate with a ratsnest of breadboard wiring, resulting in the problem you saw.
You just were lucky that changing the gate resistors fixed it.
Leo..